Development, Statistical Optimization, and Characterization of Resveratrol-Containing Solid Lipid Nanoparticles (SLNs) and Determination of the Efficacy in Reducing Neurodegenerative Symptoms Related to Alzheimer's Disease: In Vitro and In Vivo Study.

Resveratrol (RSV), as a natural polyphenol exhibiting antioxidative properties, is studied in the treatment of neurodegenerative diseases. However, RSV has low oral bioavailability. In this study and in order to overcome the issue, RSV was encapsulated into the solid lipid nanoparticles (SLNs). In this study, RSV-loaded solid lipid nanoparticles (RSV-SLNs) were prepared by the solvent emulsification-evaporation technique, and their physicochemical properties were optimized using Box-Behnken response surface methodology. The morphology of the particles was evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The neuroprotective effects of the nanoparticles were investigated in animal models using the Morris water maze (MWM). Then after, the rats were sacrificed, their brains were collected, and the extent of lipid peroxidase (LPO) as well as the level of reduced glutathione (GSH) were determined in the hippocampus section samples. Finally, the collected brain tissues were histologically studied. The particle size, polydispersity index (PDI), zeta potential, entrapment efficiency (EE%), and drug loading (DL%) of the optimized nanoparticles were 104.5 ± 12.3 nm, 0.322 ± 0.11, -3.1 ± 0.15 mV, 72.9 ± 5.31% and 14.6 ± 0.53%, respectively. The microscopic images revealed spherically shaped and nonaggregated nanoparticles. The in vivo studies demonstrated higher efficiency of RSV-SLN in the reduction of escape latency time and improvement in the time spent in the target quadrant compared to free RSV. Moreover, it was demonstrated that RSV-SLN posed a higher potency in the reduction of LPO as well as elevation of the GSH levels in the brain samples. The histological studies revealed a decline in neural degeneration and an improvement in the CA1 pyramidal cell morphology. The obtained data revealed that RSV-SLNs caused more reduction in Alzheimer-related symptoms rather than free RSV.